I have three of these systems now, 2 of the VTX10's and one VTX10R's. Very simple and easy to use. I find them easier to set up than the other brand, which can be pretty easy as well. Super smooth throttle response but I like that you can adjust it in a few ways.
I'm running my VTX10R in my SC10 4X4 and after some toying with it, I have my 5.5t 540 size motor just flying with it. I prefer the 540 power band and feel. I had to turn a bunch of settings way down but it's getting stupid speeds down the straights and still making jumps the 550 size guys can't make.

Very excited to see what's coming next from Viper!!